Summit County, CO Insulation Payback
Summit County, CO: what topping up your attic actually costs
Summit County, Colorado is zone 7 under DOE's climate map (Very Cold), which means a climate where the heating season stretches across most of the year. An uninsulated attic there should be built up to R-60. Going from R-2 to the recommended R-60 costs roughly $3,480 installed for a typical attic (about 1,000 sq ft), and pays for itself in about 1.2 years at an estimated $2,871/year saved. That's about as fast as attic paybacks get.
Heating vs. cooling in Summit County
Cooling barely factors in here; essentially the full $2,871/year is heating savings. Out of every 100 US counties tracked here, Summit County's savings potential beats roughly 99 of them. Within zone 7 specifically, it ranks 9th of 120 counties by estimated savings. Colorado averages $2,043/year across the counties tracked here; Summit County comes in 41% higher.
Where these numbers come from
The heating and cooling degree days behind this estimate — 10,736 HDD and 0 CDD (base 65°F, 1991-2020 normals) — come from DILLON 1 E, CO US, the nearest NOAA station with published normals, 5.5 miles from Summit County's center. Combined heating and cooling load puts Summit County in the 99th percentile of this 3,162-county dataset.
Already have some insulation?
If Summit County's attic already has 3-4 inches of old insulation (about R-11) rather than bare joists, the recommended target drops to R-49. That smaller top-up costs around $2,280 and saves an estimated $419/year — payback about 5.4 years. That is a solid payback as home upgrades go.
Quotes and materials for this job
Real bids depend on how easy the attic is to reach and whether old insulation needs removing first, so treat $3,480 as a starting estimate for a Summit County job, not a quote. Expect at least a $600 minimum charge from most contractors.
Nothing here is a guess
Every figure on this page traces to DOE/IECC climate zones and NOAA degree-day normals, documented in the methodology guide. The guide to what R-value actually means explains why R-60 is the target here specifically.